A conventional steam iron has a base provided with an ironing surface and a vaporizing chamber, and a heater that is integrally incorporated in the base and heats the base. The base has the vaporizing chamber for steam generation provided on an upper surface side of the base, and the ironing surface provided on a lower surface side of the base. A temperature of the base is adjustable, for example, in a range from 80° C. to 200° C., in accordance with clothing or the like that is an object to be ironed.
The steam iron has a “steam-ironing mode” for ironing with steam, and a “dry-ironing mode” for ironing without steam.
In a case of the dry-ironing mode, a reduction in the temperature of the base in ironing is small, and the ironing surface can be easily maintained at a set temperature by electric conduction control of the heater. On the other hand, in a case of the steam-ironing mode, heat is lost due to vaporization of water to be supplied to the vaporizing chamber, and the ironing surface is cooled by clothing or the like containing condensed water from jetted steam, so that the temperature of the base is reduced.
Vaporization capability depends on a temperature. When the vaporizing chamber is made to have a high temperature, the vaporization capability is improved, and a large amount of steam is generated. At a low temperature, the vaporization capability is lowered, and an amount of generated steam is reduced. When the temperature of the vaporizing chamber is increased, a temperature of the ironing surface provided in the base also increases. When the temperature of the ironing surface is reduced, the temperature of the vaporizing chamber provided in the base also reduces.
Accordingly, when the ironing surface is set to a low temperature suitable for chemical fibers weak against heat, the temperature of the vaporizing chamber reduces, and the amount of steam reduces, so that ironing in the steam-ironing mode becomes difficult.
In order to solve this problem, applications for the following prior techniques are filed.
PTL 1 discloses a steam iron that includes a vaporizing chamber having a heater, and a heat sensing unit for temperature control, and is provided above a base with a space, and that properly controls a temperature of the vaporizing chamber without being affected by the temperature of the base.
PTL 2 discloses a steam iron that includes a base and a vaporizing chamber, each of which is provided with a heater and a temperature detector, and that controls a temperature of an ironing surface and a steam amount in accordance with clothing or the like.
PTL 3 discloses a steam iron that has a first base provided with a vaporizing chamber, and a second base provided with an ironing surface, and is provided with a thermally resistive layer being an air layer separated by an outer peripheral rib and a steam rib between the first base and the second base. In this conventional technique, a temperature of the first base is set to be high, the thermally resistive layer is used as a steam staying layer, and steam is jetted after heat is discharged by the second base.
PTL 4 discloses a steam iron that is provided with an ironing surface on a lower surface side of a vaporizing chamber heated by a heater, with a heat insulation part interposed between the ironing surface and the vaporizing chamber, and that controls supply of heat from the vaporizing chamber to the ironing surface to jet steam while maintaining the ironing surface at a low temperature.
PTL 5 discloses a steam iron that has a lid for covering an upper surface side of a first base provided with a vaporizing chamber, and a space part provided with an ironing surface member on a lower surface side, and that jets steam generated by the vaporizing chamber through the space part.
PTL 6 discloses a steam iron that has a base provided with a vaporizing chamber, and a steam passage provided on an upper surface side of the base and provided with a labyrinth, and that jets steam from steam holes of an ironing surface via the labyrinth.
However, when an ironing surface is set to a low temperature suitable for clothing or the like, the steam amount reduces by considerable lowering of vaporization capability, and a favorable wrinkle smoothing effect by steam is not obtained. When a water supply amount to a vaporizing chamber is increased in order to increase the steam amount, since vaporization capability is insufficient, steam containing water droplets which are not vaporized is jetted, so that clothing or the like is moistened.
Therefore, even in a case where the ironing surface is set to a low temperature, the vaporizing chamber is heated up to a temperature suitable for generation of steam, so that it is possible to jet a proper amount of steam in accordance with the vaporization capability from the low-temperature ironing surface to attain ironing.
However, in order to iron chemical fibers or the like, for example, in a case of an iron configured such that a temperature of an ironing surface can be set to 130° C., for example, when the vaporizing chamber is heated to 160° C. being a temperature suitable for generation of steam, the following problems occur.
In such an iron, when the vaporizing chamber is heated up to a predetermined temperature by electric conduction, the electric conduction to the heater is stopped by a thermostat. However, after the stop of the electric conduction, the temperature of the vaporizing chamber continues to increase, and exceeds the predetermined temperature.
On the other hand, heat conduction from the vaporizing chamber is restricted such that a desirable temperature difference is generated between the ironing surface set to a low temperature and the vaporizing chamber heated to a high temperature, and therefore the temperature of the ironing surface increases later than the temperature of the vaporizing chamber.
Generally, when electric conduction to the heater is stopped by the thermostat, an iron is in a usable state. However, as for a temperature of the base at a start of use, while the temperature of the vaporizing chamber exceeds a predetermined temperature, the temperature of the ironing surface is slightly lower than a desirable temperature.
Accordingly, although steam generated by the high-temperature vaporizing chamber is steam generated by proper vaporization capability, the steam being in a favorable state where water droplets are not contained, there is a possibility that the steam is cooled when jetted from the low-temperature ironing surface, and dew condensation water is mixed in steam to be jetted.
Additionally, in a case where a space or the like is provided between the vaporizing chamber and the base to keep the temperature of the base at a desirable low temperature, it takes time until the temperature of the base increases to a temperature suitable for ironing.